Saving Electricity And Saving Money - Electrical Engineers Create Money-Saving Light System

May 1, 2007 — A photosensor paired with a dimming ballast controls fluorescent lighting and adjusts lights all over the user's home. A microcontroller automatically calibrates amounts of daylight and adjusts electrical light accordingly.

Lighting an office building can cost a lot of money, and sometimes those lights are left on even when natural sunlight is pouring through the windows. Now, an easy solution, called DaySwitch, makes the most of those sunny days at work and soon, at home.

"Lighting has a big impact on our lives but we pay the price because it uses a lot of electricity," says Andrew Bierman, M.S., a lighting research scientist from Rensselaer Polytechnic Institute in Troy, New York. Lighting makes up 25 percent of energy consumed by businesses. However, businesses could soon lower their electric bills.

Bierman developed the DaySwitch; it uses natural light to conserve electricity. "DaySwitch is an automatic device that will simply shut the lights off when there is plenty of daylight available," he explains. The DaySwitch is a tiny sensor that measures sunlight in an area and then it sends a signal to turn lights on or off as needed.

Bierman told DBIS about the inspiration behind the invention. He says, "You don't have to have the electric lights on when they are really not providing any more useful light than you already have with daylight."

Unlike typical lighting controls, the DaySwitch is easy to install and costs less than $25 per system. After it's installed, an easy-to-use remote control can reset the sensor to your desired level, so there is no need to call expensive electricians. When natural sunlight brightens the space, the lights go off, which cuts the lighting needs of a building in half, therefore saving on energy costs.

DaySwitch could be available for homes within a year.

The Optical Society of contributed to the information contained in the TV portion of this report.

BACKGROUND: Scientists at Rensselaer Polytechnic Institute's Lighting Research Center have developed a simple, cost-effective, energy-saving device designed to harvest daylight automatically. Unlike traditional systems where one sensor controls many lamps at once, the Dayswitch controls light fixtures individually, providing flexibility for on/off control and simple installation.

ABOUT DAYSWITCH: The Dayswitch eliminates wasted or unwanted electric light by sensing when enough daylight is available to take the place of electric light, and then responds by turning off the fixture. When daylight decreases, the device turns the light back on. A built-in microcontroller automatically calibrates the Dayswitch, allowing for easy installation and maintenance. Although it's made for office buildings with large sunlit spaces -- such as at the concourse of a mall -- the Dayswitch system can be installed anywhere, including private homes. It can even be more energy-efficient in homes, since most homes use incandescent lamps, which require more energy than fluorescent lamps.

LET THERE BE LIGHT: Typical daylight harvesting systems include a photosensor paired with a dimming ballast -- a device that regulates the electricity supplied to a lamp -- to control fluorescent lighting, dimming or brightening the lights according to the amount of daylight entering the workspace. However, full-dimming ballasts are expensive, and photosensors are difficult to program and install. Dayswitch works with all conventional fluorescent ballasts, and has simple circuitry and on/off operation, making it less expensive than similar daylight control systems.

SENSORY FEEDBACK: A sensor is a type of transducer: an electronic device that converts energy from one form to another. For instance, microphones convert sound waves into electrical signals, while speakers receive the electrical signals and convert them back into sound waves. There are many different kinds of sensors, but most are electrical or electronic. A photosensor is an electronic component that detects the presence of various wavelengths of light: visible, infrared, or ultraviolet for example. The electrical conductance will change in response to the intensity of the light being detected, and this change is recorded by a computer.

Note: This story and accompanying video were originally produced for the American Institute of Physics series Discoveries and Breakthroughs in Science by Ivanhoe Broadcast News and are protected by copyright law. All rights reserved.